Patients infected with the human immunodeficiency virus (HIV) and primary care outpatients will be two of the major foci of health care evaluation in the 1990's, which will emphasize outcomes research, quality and effectiveness of care, technology assessment, practice guidelines, and cost control. Mortality data, while important, will not suffice: quality of life data will be pivotal. At present, however, there is no consensus on how to assess quality of life. Furthermore, a preliminary study has shown that three approaches to quality of life assessment--the clinical epidemiologic (which assesses functional capacity), the health services research (which measures health status), and the decision analytic (which assesses utilities, or patient preferences)--generally correlate poorly. The proposed 12-month project seeks to assess quality of life in 120 patients with HIV infection and in 120 primary care outpatients using six quality of life instruments representing the three disciplines. Patients will be interviewed serially to address the following specific aims: 1. To assess the relationship among quality of life measures based on clinical function, health status, and utility theory across a broad spectrum of health and disease. 2. To explore why these measures may correlate poorly. Specifically, three hypotheses will be examined: a) whether certain other measures, in particular emotional status, correlate with utilities; b) whether the three types of measures are indeed closely related in sicker patients, namely, patients with AIDS; and c) whether clinical epidemiologic and health services research measures correlate with utilities at some point in time but diverge as patients adapt. Thus, besides obtaining disease-specific data useful for outcomes research, cost-effectiveness analyses, and other health services research , the proposed study will further analyze the relationships among several kinds of quality of life measures in the hope of developing the basis for a future synthesis-of quality of life assessment.